https://www.acwing.com/problem/content/682/

#include<bits/stdc++.h>
using namespace std;
double len[100010];
 int n,m;
int solve(double a)
{
      int sum=0  ;
      for(int i=1;i<=n;i++)
      {
          sum+=len[i]/a;
          if(sum>=m)return 1;
      }
      return 0;
}
int main(){
   double l=0,r=1e9;
    cin>>n>>m;
    for(int i=1;i<=n;i++)cin>>len[i];
    while(r-l>1e-3)
    {
        double mid=(r+l)/2.0;
        if(solve(mid))l=mid;
        else r=mid;
    }
    printf("%.2lf\n",l);
    return 0;
}